Various reagent cartridges for use in protein analyzers and other automated clinical analyzers are known.
Fechtner U.S. Pat. No. 5,075,082 describes a reagent cartridge for use in an automated clinical analyzer having a plurality of independent storage compartments and including a body member and a bottom wall. The body member and the bottom wall are separately formed by injection molding and then the individual parts are welded together using a metal plate heated to an elevated temperature which renders the adjoining surfaces of the body member and bottom wall fusible. In the Fechtner cartridge, the chambers for storing fluids are formed by the joinder of the bottom wall to the body member.
Boris et al U.S. Pat. No. 5,031,797 describes a reagent cartridge which has a plurality of chambers for containing fluid reagent, each chamber having an entry port and resealable seal means for receiving a probe used to withdraw reagent from the cartridge. A vent in the form of sealing or adhesive tape is provided for each chamber in the top closure. One end of the cartridge has a flange extending outwardly therefrom which includes a plurality of vertically aligned openings or windows through which an optical signal may be transmitted. The floor of the chambers have necks with access openings sealed with an elastomeric membrane which can be pierced by the probe to remove fluid reagent. The floor and the side and dividing walls of the cartridge are molded of a single piece. The top closure is fastened to the side and dividing walls by ultrasonic welding or by adhesive fastening. Ultrasonic welding is difficult to control and tends to yield significant numbers of units which are poorly bonded and prone to develop leaks. In addition, the use of ultrasonic welding tends to locally denature the resin from which the units are made. Consequently, both welded and adhesive bonded units are not homogenous in chemical composition over the entire unit.
The cartridge of the present invention is a one piece design using a low cost commodity resin which is recyclable, whereas the two piece designs of the prior art, which are either thermally welded, bonded together on a special heat metal plate fixture, or joined by adhesives, are "non-recyclable". The two piece design also places severe constraints on the types of resins which may be used since they must be inert to the reagents as well as "bondable" to each other. Because of this and the elimination of assembly tooling and procedures, the cartridge of the invention has a lower production cost.
The single piece cartridge of this invention has molded-in threads for one or more reagent chambers or wells which are adapted to receive screw-on caps including screw-on vented caps. The single piece cartridge may also contain "thinned out" areas strategically located to permit the observation of the fluid levels within the wells at any time. These and other advantages of the present invention will be apparent to those skilled in the art from the following more detailed description.